Class Sizes

Parents, teachers, headteachers and governors agree that excessive class size is detrimental to the education of children.

In England and Wales, there is no statutory limit on the size of any class above Key Stage One (KS1). Local authorities, governing bodies and academy trusts are subject to a statutory duty to limit the size of infant classes for KS1 children taught by a single qualified teacher to 30 or below.

There are some limited exceptions to this rule, particularly in relation to the admission of pupils with special educational needs and disabilities (SEND) and siblings.

Further information on requirements in England is available in the School Admissions Code. Information for Wales is available from the Wales Assembly (pdf).

In Scotland, class size limits are set out in Part 2, Appendix 2.9 of the Scottish Negotiating Committee for Teachers (SNCT) Handbook. These limits vary according to factors including pupils’ age, phase of education, the nature of the subject being taught, and pupils’ Additional Support Needs (ASN).

In Northern Ireland, the Secondary School (Grant Conditions) Regulations (Northern Ireland) 1973, Regulation 15 stipulates that the maximum limit for a practical class is 20 pupils except where approved by the Department of Education. NASUWT action in Northern Ireland has succeeded in ensuring that the vast majority of schools apply this limit.

As a trade union, the NASUWT is most concerned that increasing class sizes impose greater workload on teachers, which is unreasonable and unacceptable and must be resisted.

The majority of education systems in the OECD set out statutory maximum class sizes across all age groups, although in some systems, such as Finland and Sweden, such limits are set at local authority level.

There are four key reasons a limit on class size is worthy of consideration. Lower class sizes:

  • have a positive impact on learning;
  • provide support for efforts to reduce teachers’ workload;
  • are valued by parents; and
  • help keep learners and staff safe.

Impact on learning

There is powerful evidence that class size can have a significant impact on learning. Studies that avoid these limitations appear to indicate that limiting class size can have a powerful impact on pupils’ educational experiences.

The Student/Teacher Achievement Ratio (STAR) project in Tennessee and the Class Size and Pupil Adult Ratio (CSPAR) study in the UK, both of which were based on primary rather than secondary research, supported the view that class size had positive implications for pupils’ learning, particularly for younger pupils, those from disadvantaged backgrounds, and those with levels of achievement lower than those evidenced by the majority of pupils of their age.

Other studies have pointed to the benefits for the development of pupils’ non-cognitive skills (such as persistence and engagement) of smaller class sizes. Evidence based on primary research also suggests that smaller class sizes can have positive benefits for pupils from Black communities and for those for whom English is an additional language.

Limiting workload

Setting some limits on class size can also make an important contribution to limiting teacher workload and enhancing working conditions.

Literature reviews of teachers’ reported experience confirms that reductions in class size can have a positive impact on teacher workload and levels of stress. This is to be expected, given that teachers in the UK and elsewhere report excessive class size as key driver of excessive workload. Teachers report consistently that smaller class sizes reduce burdens in relation to planning, assessment (including marking), and record keeping.

Views of parents

Evidence suggests that parents place significant emphasis on class size.

One study conducted in the UK indicated that three-quarters of parents knew the exact number of pupils in their child’s class. Around six in ten parents believe that there are an excessive number of pupils in their child’s class, while over 96% of parents believe that the number of children in a class influences the quality of children’s educational experience.

Studies in other jurisdictions also reflect the importance placed by parents on the issue of class size.

A poll conducted for the Independent Schools Council highlighted class size as a reason why parents may express a preference for schools in the independent sector. A quarter of respondents to this survey stated that a key reason for this preference was the relatively smaller class sizes found in the independent sector.

Keeping learners and staff safe

The NASUWT continues to highlight the health and safety dimensions of class size.

The Health and Safety at Work etc. Act 1974 and the Health and Safety at Work (Northern Ireland) Order 1978 require employers to provide a healthy and safe working environment for staff. They also require that children and young people are educated in settings that secure their wellbeing and where risks are managed sensibly.

Irrespective of any statutory limits, in any lesson, but especially those in practical subjects, members should risk assess the suitability of the physical environment for the planned activity, taking into account the number of learners expected and the adult to learner ratio. If the member deems the activity to be potentially unsafe, it should not be undertaken. If the activity forms a required part of the curriculum, concerns should be raised with the school management, either directly or through the NASUWT Representative. Further advice can also be obtained from the NASUWT.

For all these reasons, the NASUWT will continue to campaign to ensure the current protections in respect of class size remain in place and will defend members robustly if their legitimate interests in these respects are placed at risk.

If you have any concerns about class sizes in your school, please contact your NASUWT School Representative. Alternatively, you can email the Member Support Advice Team. Members in Northern Ireland, Scotland and Wales should contact their National Centre.


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